I'll keep the introductions short. My name is Matt, and I am - was - an avid fan of urban exploration.

If you've never heard of it, the short explanation is this: in any city or town, there are multitudes of abandoned, hidden places that most people don't even know exist. Old, unused railway stations. Miles and miles of tunnels. Hell, even whole reservoirs of water.

Urban exploration is the practice of finding and exploring such places. I got into it when I was seventeen, and ever since then, I've been hooked.

Good thing too, seeing as I'll be spending my entire life in the underbelly of this city, hunted by an uncaring government that probably wants me dead to ensure my silence.

The man who went through this horror with me, who I know only as Rodriguez, sits next to me. He too will spend the rest of his life hidden away, a mute observer and confidante as I write these words.

I don't hope to forget what I've seen. That will never happen. The best I can hope is that, after reading this, you too will see the truth, one day.

So, here goes.

The day it began, I left my house in the morning, full of excitement. I'd received a tip from a fellow urban explorer about some sort of old, abandoned complex deep beneath our city. She’d sounded ecstatic about her find, which I could hardly believe – she was an explorer far more experienced than me. This place really had to be quite something to get her this worked up.

She told me that it looked like some kind of semi-military installation, abandoned for God-knows-how-long. Perhaps a WW2-era resistance hideout, she'd theorized. As if I'd needed more reason to see the place.

I had my usual gear with me: a flashlight, a coil of rope, a first aid kit. I wasn't expecting any trouble, but it pays off to be ready.

Exiting the surface through an innocuous-looking rusted door, I walked, climbed and, in places, crawled for an hour through a series of ducts, chutes and cable-strewn passageways. It was clear that this was not the "correct" entrance to wherever I was going, but rather an ad-hoc infiltration route.

Already, I was captivated.

Finally, I dropped down from a grimy air duct, lifted my light and looked around in wonder. My friend hadn't been exaggerating: this place was an urban explorer's dream.

I was in a large, circular room with four exits, apparently a crossroads of some sort. Narrow passageways led off in every direction of the compass, all but one sloping upwards. The last led steeply downward. The floor, covered in a deep coating of dust, was broken up by waist-high concrete blocks, with shallow trenches excavated behind each one.

Looking back on these events, I realize one thing: these concrete blocks, obviously intended to take shelter behind, were all facing towards the single downward-heading passageway.

Whoever had built this place hadn't intended to defend against an attack from the surface, but from beneath the ground.

In my excitement, I somehow managed to ignore this fact. After taking a photo of my surroundings, I continued down one of the passageways. Obviously, I took the one heading downward.

The corridor went on for about half a mile, before ending at a large iron door, an iron circle set in its centre. I grabbed it and pulled. At first, it wouldn't budge, but after several hard pulls, it swung open with a squeal of rust-covered hinges.

Beyond was another room, this time with only a single other corridor, again leading down. I gasped. The centre of the room was dominated by a wide wall of sandbags. Several heavy machineguns, the kind you see in scenes of trench warfare, were mounted on the top. All were pre-aimed at the corridor heading downward.

I went closer, rummaging for my phone. This was unlike anything I'd ever seen while exploring. Old, abandoned underground stations were one thing. Goddamn machine gun nests were another.

As I approached, I frowned in confusion. The floor was covered in a heavy coating of dust, but around the sandbags, large, booted footprints were imprinted in the grime. I stooped down to take a closer look.

These prints were fresh, days old at the very most. Someone had clearly been tending to this place recently. I shone my light up. The trail led off into the dark of the downward corridor.

A small, nagging doubt pulled at me. Someone was clearly using these tunnels. Might it have been my friend? No, that couldn't be it. She'd have told me if she’d found something like this. Besides, if these were her tracks, they'd have come from the surface.

I should've turned back at that point. Why didn’t I? Some goddamn curiosity, the thrill of discovering something new, stopped me from doing the reasonable thing. I stayed where I was like an idiot, staring at my strange find.

A half-heard sound up ahead made me look up. I got a split-second glance of movement, a dark figure moving at the corridor entrance, before all hell broke loose.

A bright, blinding flash of light turned my vision into white fire. There was a sound like rolling thunder, all around, unceasing. I was blind and deaf. Distantly, as if in a dream, I felt myself falling to the ground under the sensory assault.

A second and yet an eternity later, the attack on my senses stopped. Through the ringing in my ears, I heard the stomp of boot-clad feet.

"Contact!" someone yelled in the whiteness my sight had become. There was a loud bang, and something impacted the concrete right next to my neck.

I'm being shot at, I thought numbly.

"Hold fire!" yelled another voice, deep and authoritative. "I've got no reading on the spectrometer! It's not one of them!"

"What if it's a ghoul?"

A third voice. "Ghouls don't get caught unawares like this. He's a civvie. Get your gun out of his face, for Christ's sake."

"What's a civilian doing down here, Rodriguez?"

"No idea." That was the commanding voice again. "Bag him. He has to come with us."

Rough hands gripped me. I swung blindly at their owner and missed. A split second later, something with the force of a sledgehammer hit my face. I staggered, reeling from the impact. Before I could recover, a rough bag was placed over my head. I screamed. Another blow.

"Don't struggle." came the voice again. "If you do, I am authorized to use lethal force to neutralize you."

"Please, I-" I began.

"You will remain silent. You will not struggle. You will come with us. Nod if you understand."

My mind raced, adrenaline and panic threatening to overcome me. I was blind, miles from the surface, and surrounded by armed people. In under a minute, this trip had gone from intriguing to horrifying.

I nodded mutely.

"Get him up." came the voice. Someone hauled me to my feet and led me forward, stumbling and blind, deeper underground.

At first, I tried to keep my wits about me, remember the distances and directions we took. If I could somehow escape these people - whoever they were - I'd need to backtrack to find my way out and to the surface. Soon, however, I gave up. The disorienting, suffocating blackness of the bag made it impossible to keep any sort of bearings.

Once, after half an hour of silently stumbling through the dark, I tried to beg with my captors.

"Please," I began. "I don't know anything. I was just-"

I didn't get further. A hand clasped over my mouth, almost suffocating me with the heavy fabric.

"You will remain silent at all times. This is for the safety of both you and my men. If you endanger us one more time, I will be forced to neutralize the threat you pose."

I shut up very quickly after that.

Another unknown span of time passed. I didn't know how far or how long we'd been travelling, when suddenly, a loud, electronic beeping broke the trudging silence. I heard one of my captors curse under their breath.

"Shit. I've got a reading. A hundred metres ahead and closing."

There was a quiet clack of unholstered weaponry.

A hand pressed down on my back, forcing me to lie flat on the ground. I felt someone's hot breath next to my ear.

"Whatever you do, remain absolutely silent." That was the voice of the man they'd called Rodriguez. "Don't move. Breathe quietly unless you want to be found. And trust me - you don't want to be found."

The beeping got more insistent, higher - pitched.

"Fifty metres," someone said.

"Lights out. Sound down."

The beeping stopped - no, I could still hear it, but muffled, incredibly quiet, echoing from an earpiece. It was growing faster, more insistent.

Breathe quietly unless you want to be found.

The shallow inhale-exhale of my captors and the blood pounding in my ears suddenly seemed as loud as a thunderstorm.

For a few, terror-filled seconds, there was absolute silence.

And then...

"Dead ahead!" one of the soldiers yelled.

The air exploded with the sound of gunfire. It was an unceasing hammering as my captors emptied their clips, ran dry, reloaded and fired again. Strobing light flashed through my hood. The stench of gunpowder choked my throat. I almost screamed.

The fire died off as quickly as it had begun. There was a click as someone slotted a new magazine into their rifle.

"Movement?"

"Negative."

"Spectrometer?"

"No readings."

"It's either dead or escaped. Get the civvie up. We need to move, before more of them arrive."

I was hauled to my feet. This time, we didn't walk down the corridor, but went at a brisk jog, strong arms holding me up whenever I stumbled.

Finally, just when I thought I couldn't take any more, we stopped. There was a grinding of iron hinges.

Through the black bag over my head, I could hear voices, the hum of machinery, the bustle of activity. The air changed, becoming warmer, more packed. Somehow, I knew I was in a massive room, or maybe a cave. There were unseen people all around me.

I was led forward again, up a steep flight of stairs and along some sort of gangway. A door squealed open, then shut behind me.

Without warning, the bag came off my head, and I squinted at the sudden light. I looked around, amazed, afraid and confused in equal measure.

I was standing in some sort of large office. Maps and reports papered the grey concrete walls. A heavy steel table dominated the centre of the room. Behind it, mounted on the wall, was a massive electronic display, showing an intricate map of interweaving corridors, rooms and caverns. Various points on the map glowed green, while several blinked a threatening red.

A man stood behind the desk. He was tall and muscular, with salt-and-pepper hair, dressed in combat fatigues and a plain black shirt. A gun was holstered at his waist.

Before I could say anything, he held out his hand to me.

"My name is Major Rogers. I'm sorry for the rough treatment you've had, but it was, unfortunately, quite necessary."

Utterly confused, I took the offered hand and shook it limply.

"M-Matthew Daniels."

Rogers smiled at me, though it was a forced expression.

"I'm sure you have many questions, but I'm afraid I can't answer any of them. In fact, you'd do best to forget everything you've seen and heard here."

"I- I'm-" I began.

"Please, take some time to collect your thoughts." Rogers said. "There are certain matters we must discuss, and it's best if you have your wits about you before we begin."

I swallowed the thousand questions I was thinking of, forcing my racing mind to stop and assess.

"What is this place?" I asked finally.

"That's classified." Rogers answered.

"What the hell is going on?" I said, forcing an edge of anger into my voice.

"That's also classified. Like I said, I can't tell you anything."

"Then... What's going to happen to me?"

Rogers sighed.

"I'm afraid you're going to have to stay here for a while, possibly even a few days. I don't have the authority to make the call of what to do about you. We've notified command of your presence, and someone with higher clearance will be on their way shortly. My guess? You'll sign enough NDAs to bury yourself under, then you'll be given a new identity and relocated to somewhere where no one knows who you are."

My head swam. This was insane. This couldn't be real. This was-

"You... You can't do this." I whispered incredulously. "I have rights. There's no way-"

"I'm afraid none of that matters down here. Not in this war."

I leapt to my feet, the chair crashing down behind me.

"You son of a bitch, you let me go right n-"

The door opened behind us. A grim-faced woman, a pistol gripped in her hand, peered inside. My heart sank.

"Everything alright, sir?"

"Yes, corporal." Rogers said calmly. "Leave us, please."

The woman glanced at me, then shrugged and closed the door again. I collapsed in my chair, defeated.

"I understand this is hard to come to terms with. I will have my soldiers escort you to your temporary quarters, where you can gather your thoughts. Then, we-"

Without warning, a wailing siren drowned out the major's words. He wheeled around. On the screen behind him, green lights were rapidly turning red, all over the map.

All converging on one place.

From outside the office, I heard frantic activity, snatches of desperate reports and orders.

"Spectrometers 12 through 47 triggered-"

"I've got movement in all the western tunnels-"

"This is Delta Camp, requesting immediate-"

Rogers grabbed a microphone from his desk, keyed it on, and brought it to his lips.

"Code Black, I repeat, Code Black." he said, his voice tense. "The perimeter is breached. They’re coming."

Part 2

Part 3

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